The invention relates to field of user interfaces for computers and electronic devices. Keyboards are the most common input devices for computers. Keyboards enable computers to receive text and other complicated inputs. However, portable electronic devices, including handheld computers, electronic organizers, personal digital assistants, portable game systems, wireless phones, are often too small to include a standard size keyboard. As a result, they require alternative input devices for receiving text and other complicated inputs.
One user interface displays a virtual keyboard on a screen and allows users to manipulate a cursor, using a joystick, directional pad, or other input device, to select letters on the virtual keyboard. This approach is time-consuming, often requiring many button presses to select each letter.
One user interface includes a small keyboard designed to be operated by a user's thumbs. Unfortunately, the thumb keyboard requires two hands to operate, is too large for many portable electronic devices, and has a steep learning curve.
Another user interface input device maps letters of the alphabet to the keys of a standard telephone keypad. A set of multiple letters is mapped to each of at least a portion of the keys. To enter text, the user presses each key one or more times to select one of the set of letters associated with that key. A selection is completed by waiting for a predetermined period of time or by pressing another button. One disadvantage of this approach is that text entry is very slow, often requiring multiple button presses and long pauses for each letter.
A variation of this user interface is referred to as T9. T9 is a predictive text input system that attempts to reduce the number of button presses required for each letter. Like standard telephone keypad-based text input, a set of multiple letters is mapped to each of at least a portion of the keys. To enter words, the user only needs to press each key associated with a letter once. Because there are multiple letters associated with each key, an input sequence can correspond to many different combinations of letters. As the user enters a word, the system accesses a dictionary or other database to identify the word or words likely to correspond with a given input sequence. If there are multiple words associated with a sequence of inputs, the user interface allows the user to select the desired word. Although telephone keypads take less space than a thumb keyboard, few devices besides wireless phones have telephone keypads. Additionally, these user interfaces are limited to text input and are difficult or impossible to use with languages having a large number of characters, such as Chinese and Japanese.
It is therefore desirable for a user interface of an electronic device to enable quick and efficient entry of text and other complicated inputs. It is further desirable for the user interface to use minimal space for input devices and to be easily integrated with a wide variety of types of electronic devices. It is also desirable for the user interface to enable users to enter text for languages having a large number of characters. It is desirable for the user interface to handle non-text input. It is desirable that the user interface can be operated with only one hand.